Tunnel furnace



May 28, 1946. G, MYHRMAN TUNNEL FURNACE 2 Sheets-Sheet l Filed NOV. 27, 1944 G. MYHRMAN TUNNEL FURNACE Filed Nov. 27, 1944 2 sheets-sheet 2 INVENTbR:

Patented May 28, 1946 Georgel Myhrman,

McKeesport, Pa., assignor to National lllube Company, a corporation of New Jersey Application November 27, 1944, Serial No.7565 ,333

9 Claims. (Cl. 214-18) e This invention relates to improvements inA furnaces, and more particularly to furnaces wherein tubular articles and the like are heated while being longitudinally conveyed therethrough.

Itis .frequently necessary in the manufacture of tubular products to elevate the temperature of the partially processed product before subjecting it to a subsequent forging or rolling operation. Since the product retains a great deal of heat from prior heating, the temperature may be raised suil'ciently by passing it through an elongated furnace usually referred to as a tunnel furnace. Since such furnaces are in the production line, the furnace should be sufficiently long to elevate the temperaturev the desired amount while the article is conveyed longitudinally therethrough in the line of production. Frequently this entails making the furnace too long to be efficiently operated or as is sometimes the case, space limitations will not permit a furnace of such length.

Accordingly, it is an object of the present invention to provide tunnel furnaces having improved heating capacity.

It is another object to increase the heating capacity of. tunnel furnaces without increasing the length thereof.

It is a further object to provide a tunnel furnace having an improved operating efficiency.

The foregoing and further objects will be ap` parent from the specification and drawings wherein:

Figure l is a plan view of a tunnel furnace embodying a preferred form of my invention;

Figure 2 is a side elevation-thereof; and

Figure 3 is a vertical cross section taken on line III-III of Figure l.

Referring more particularly to the drawings, the numeral 2 designates the body portion of a tunnel furnace having an elongated chamber or passageway 3 therethrough. Roller conveyors d provided in the chamber 3 are suitably driven by motors for conveying tubular workpieces therethrough. The furnace chamber 3 may be heated by burners 8 connected to the air and gas mains l and 8. Also provided in the chamber 3 above and to eitliei--side of the rollers 4 are shelves or supports il and 9. the upper surfaces of which are preferably concave as at I9 for a purpose which will be more fully described hereinafter.

Suitably disposed along the lower side of the chamber 3 and intermediate the roller conveyors l! are a series of pairs of lifting members or manipulators l5 and l5' mounted for reciprocation in a vertical plane in pedestal supports or guides il' andll. Lifting members I5 and l5 comprise an upper portion 20 and a depending leg 2l which reciprocates in a slideway 22 in the pedestals and Il. The lifting members are operable by means of levers 23 fixed as at 24 to shafts 25. The shafts 25 may be partiallyk rotated by levers 23' keyed thereto at their lower end and which is pivotally connected at their upper end to piston rods 21 and 21. The pistons 26 and 26',

in which the piston rods 21 and 2l' are mounted for reciprocation, are connected to a suitable source of fluid under pressure by pipes 28 through 4-way valves 29 and 29. Thus, it is seen that operation of the valves 29 and 29' will admit fluid under pressure to the front portion of the cylinders 26 and 26 and thereby move the levers 23 upwardly to elevate the manipulators I5 and l5.

Thelifters or manipulators |5 disposed to the right of the roller conveyors 4, as shown in Figure 3, have their upper surfaces 20 divided into two slanting surfaces 3| and 32 connected by a curved substantially upright portion 33. Both the surfaces 3| and 32 are slanted downwardly towards the left hand side of the furnace. Portion 3| is partially aligned with the rolls 4 and is adapted to engage a tubular workpiece disposed thereon and elevate it and permit it to roll therefrom onto the shelf 9 when the manipulators 5 have been elevated sufficiently to raise the surface 3| even with or slightly above the shelf 9. Due to the upper surface of the shelf being concave, the workpiece will be retained thereon. The other slanting surface 32 extends outwardly to approximately the outer edge of the shelf 9 so that when the manipulators I5 are raised suciently high to `permit a workpiece to roll therefrom onto the shelf 9, the surfaces 32 will engage a workpiece resting on the shelf 9 and elevate it sufficiently above the shelf 9 so that it will roll downthe surfaces 32 into engagement with the upright portions 33. Upon lowering of the manipulators I 5, the workpiece will thereupon engage the inclined side 9b of the shelf 9 and be moved onto the surfaces 3| from which it is deposited onto the rollers 4 when the manipulators l5 are lowered to their lowermost position. Accordingly, it is seen that operation of the valves 29 and 29' to deposit workpieces on the shelves 9' and 9 by means of manipulators I5 and I5' at the same time removes a workpiece from the shelves 9 or 9', if a workpiece is resting thereon.

In operation, a workpiece A is moved longitudinally in the chamber 3 by conveyor rollers 4 unbi1 it iS completely inside the chamber. Valve 29 is then operated to admit iiuid under pressure to the cylinder 25 which thereby operates the lever 23, shaft 25, and lever 23 to lift the manipula tors i to elevate the Workpiece A above the shelf S. Thereupon the workpiece rolls down the inclined surface 3! onto the shelf Si. The valve 29 is then manipulated to exhaust fluid under pressure from the cylinder 26 permitting the manipulators l5 to return to their lowermost positions. As soon as a succeeding workpiece B is moved. into the chamber 3, the valve 29' is operated to admit lift the manipulators I5' and. elevate the workpiece B above the shelf 9` onto which it is deposited from the inclined surface 3|'. At the same time, the surface 32 engages the workpiece A previously deposited on shelf 9' and lifts it suilciently to permit it to roll theredown to engage the upright portion 33'. The valve 29' is then operated to exhaust fluid under pressure'from the cylinder 26', permittingrthe manipulators I 5 to return to their lowermost positions. In so doing` the workpiece A engages the inclined side 9b of the shelf 9 which moves it onto surface 3| and from thence it is deposited onto the rollers li, Thus, it is seen that by working the manipulators alternately, workpieces are deposited and removed fromalternate shelves. By so doing, they are. given additional time in the furnace whereby their temperature can be raised the required amount without lengthening the furnace unduly or maintaining an uneconomically high temperature therein.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that varw ious other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

l. In a furnace having an elongated chamber through which the article to be heated is moved longitudinally thereof by conveyor mean s. the improvement which consists in shelf members disposed on either side of said conveyor means. means for moving an article to be heated from said conveyor to one of said shelves and means for removing a previously deposited article from the other of said shelves and depositing it on said conveyor for removal from said furnace.

2. In a tunnel furnace including conveyor means for moving articles to be heated longitudinally therethrough, the improvement which consists in a plurality of vertically reciprocating members along said conveyor means some of which arek constructed and arranged to move articles to be heated to one side of said conveyor and at the same time remove a previously deposited article from the other side of said convey-or and deposit it on said conveyor and the other of said vertically reciprocating members being constructed and arranged to move an article from said conveyor to said last-mentioned side and at the same time remove the previously deposited article from the first-mentioned side and place it on said conveyor.

3. In a tunnel furnace including conveyor means for moving tubular articles longitudinally therethrough. shelf means on either side of said conveyor means and means to move tubular articles from said conveyor means to said shelf means, said means comprising centrally disposed vertically reciprocating members which are constructed and arranged to move tubular articles Vfluid under pressure to the cylinder 26' to thereby from said conveyor to either of said shelves alternately and back to said conveyor for withdrawal therefrom.

4. In a tunnel furnace including conveyor means for moving tubular articles longitudinally therethrough, alternately arranged vertically reciprocating members centrally disposed therein and intermediate said conveyor means for moving tubular members to each side of the conveying means alternately, each of said members having its upper surface constructed and arranged t0 move a tubular article lifted thereby to one side of said conveyor means and to simultaneously remove a tubular article from the other side of said conveyor means and replace said last named article on said conveyor for removal from said furnace.

5.V In a tunnel furnace including conveyor means for moving tubular articles longitudinally therethrough, supports for such articles on both sides of said conveyor means, vertically reciprocating members centrally disposed therein and intermediate said conveyor means, each of said members having its upper surface constructed and arranged to move a tubular article lifted thereby onto one of said supports and to simultaneously remove a tubular article from the other of said supports.

6. In a tunnel furnace including conveyor means for moving tubular articles longitudinally therethrough, supports for such articles on both sides of said conveyor means, vertically reciproeating members centrally disposed therein and intermediate said conveyor means, each ofsaid members having its upper surface constructed and arranged to move a tubular article lifted thereby onto one of said supports and to simultaneously remove a tubular article from the other of said supports, and to deposit said last named y 40 tubular article upon said conveyor means for removal from said furnace upon lowering thereof.

'7. In a tunnel furnace including conveyor means for moving tubular articles longitudinally therethrough, a support for such articles on each side of said conveyor means, vertically reciprocating members centrally disposed therein. each of said members having its upper surface constructed and arranged to move a tubular article lifted thereby onto one of said supports and to simultaneously remove a tubular article from the other of said supports, said lifting means being operable to` move successive tubular articles to alternate sides of said furnace.

8. In a tunnel Afurnace including conveyor means for moving tubular articles longitudinally therethrough, a support in said furnace for such articles on each side of said conveyor means, vertically reciprocable members disposed therein, each of said members having its upper surface composed of two slanting portions with an upright portion therebetween, one of said portions being aligned with said conveyor means and the other of said portions extending through said support, means to reciprocate said members to elevate a tubular article from said conveyor` means and move it onto one of said supports and simultaneously lift a rtubular article previously deposited on the other of said supports and deposit it'on said conveyor means for Withdrawal from said furnace when said members are lowered'.

9. In a tunnel furnace including conveyor means for moving tubular articles longitudinally therethrough, a support therein for such articles on each side of said conveyor means, vertically reciprocable members disposed therein, each of said members having its upper surface composed of two slanting portions with an upright portion therebetween, one of said portions being aligned with said conveyor means and the other of said portions extending through said supporting means to reciprocate certain of said members alternately to elevate a tubular article and deposit it on one of said supports and simultaneous- 1y remove the other of said supports and to deposit the succeeding tubular article on the last named support and remove'the tubular article from the rst named support.

GEORGE MYHRMAN. 

